Improved process for making



UNITED STATES PATENT OFFICE.

JOHN W. DIXON, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVED PROCESS FOR MAKINGPAPER-PULP.

Specification forming part of Letters Patent No. 51,433, dated December12, 1865.

To all '1r-hom fit may concern:

Be it known that I, JOHN W. DIXON, ofthe city of Philadelphia, State ofPennsylvania, have invented a new and useful Process ot MakingPaper-Pulp from Vood, Straw, and Vegetable Fibrous Materials 5 and I dohereby declare the following to be at'ull and exact description of thesame.

My process consists in treating straw, wood, or other vegetable fibrousmaterials by highlyheated water in a liquid state under pressure forcedby a pump to pass into and through the vegetable matter to be pulped, asa process or preparatory process for making paper-pulp; and also inforcing into the digester at i11- tervals fresh water, highly heated andunder pressure, for the purpose ot' more elteetually acting upon anddissolving the glutinous and other matters contained in the vegetablematters usually used for making pulp, by means of a pump; and I nowproceed to describe the same, reference being had to the annexeddrawing, which represents, by way of illustratiou, one .convenient formof carrying on my process.

A represents the pnlp-digester, which is a boiler made ot' strong iron,(capable ot' resisting a pressure of from one hundred to three hundredpounds,) say four feet diameter and twelve feet high. Itis furnishedwith a luanhole cover, B, and a perforated diaphragm, O, a centralremovable cover, D, and a lower perforated diaphragm, E, with a slidingvalve, as described fully in a former application for patent made by me.

F is a conical coil builtin a furnace, and connecting at its lowerextremity with the lower part of the pulp-digester A by means ot' thetubes l, 2, and 3. At 4 a rotary pump is placed in the course of thistube. 'Ihe upper part ot' the coil F is connected by the tube 6 with theinterior of the digester A at its top.

G is an iron or wooden tanksay four feet diameter and ten or twelve feethigh-open or closed. The tube 7 passes from the lower part of thedigester A through the walls of the tank G, and thence coils up and downa number of times in that tank, and passes out through the wall ofthetank at S. The interior ofthe tank is connected by the tube et with thetube 2 and the pump.

The operation of this apparatus is as follows: rI he digester A is to befilled with the vegetable fibrous matter to be pulped through themau-hole B. The cocks J and K are closed A iire is made aud the cocks Land M opened.

under the coil F vaud the digester and coil filled with fresh water.Fire is then applied under the coil F and maintained until the desiredpressuresay from eighty pounds to two hundred and fifty or three hundredpoundsis obtained, according to the nature ofthe substance to be actedupon. The pumpt is then started and made to circulate the highly-heatedwater from the bottom of the digester through the heating-coil F intothe top. After this liquid has circulated some time the cock L is to beclosed and the cock J is opened. Thus the liquid will pass through thecoil of pipe 9, 10, 11, and 12 and escape at S. The tank is filled withfresh water, which is heated by the liquid passing through the coil. Thecock K bein gopened, the water thus heated in the tank passes on throughthe tubes 5 and 2, the pump 4, and the coil F into the top of thedigester A. By this means the water filled with gummy and other matterscan be freely removed and its temperature imparted to a fresh supply otwater as it passes out. After the contents ofthe boiler A have been thuschanged the cocks J and K are to be closed and the cock L opened,whereupon the circulation produced by the pump will be resumed. as atthe first, from the bottom to the top, and so continued until the liquidbecomes again surcharged with the gummy matter.

By this means the vegetable material can be pulped without mechanicalaid in from five to twelve hours, depending on the material operated onand the pressure used.

Good results with this apparatus can be obtained with straw at onehundred and twentyfive pounds pressure, and perhaps less. With wood andother harder materials it would be preferable to use a higher te mperature-say one hundred and fifty to three hundred poundsalthough woodcan be pulped to a considerable extentat 1250 Baume, and lower, byprolonging the time.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

The process of treating wood, straw, and similar vegetable substances byforcing highly-heated water under pressure to circulate continuouslythrough the mass to be pulped by means ot` a pump, as a process orpreparatory process for making paper-pulp, substantially as described.

Witnesses: JOHN W. DIXON.

M. G. HUBBARD, J. WM. KREPPS.

